Various transfer mechanisms are indexed to move a work piece or work tool from one work station to another in an intermittent and repeating manner. For instance, an indexing conveyor may have a plurality of pallets spaced thereon which are moved intermittently to consecutive work stations. Thus, the conveyor is intermittently driven discrete distances to align or index the pallets with the various work stations.
Especially with relatively long indexing conveyors, a significant momentum or inertia is generated when the conveyor is moving such that it is very difficult to accurately stop the conveyor. Further, once stopped the conveyor may apply reactive forces to the drive mechanism causing it to shift from its desired position. Prior drives used for indexing conveyors include electromechanical or multiple cylinder pneumatic devices which are expensive, unreliable and are unable to accurately stop and thereafter hold the position of the conveyor.